As I understand it, torrents are more of a style of file-sharing (typically used for very large files), rather than a file type. It might be compressed, it might be video, it might be music, it might be executable as-is.

What I generally recommend is to look at the three-letter extension on the file and do a Google search on that extension to see what the specific type of file is. You'll usually find recommended viewers or extractors (if needed) during that same search.

*nod* Yep! I've used it to watch every type of video file I've ever encountered without a problem. I had a problem watching a .mkv file once, but that was because the file was HUEG and it was on my old wimpy computer. Here's a list of all the formats it supports: http://www.videolan.org/vlc/features.html